It is more than 900 years since the Crusaders captured Krak des Chevaliers overlooking the valleys of central Syria – lugging blocks of limestone up the steep hillside to build a fortress that still looks pretty impregnable – so lunch under the Gothic arches of its great hall is a treat that packs a powerful historical and culinary punch.

Saracens and Christian knights played by bored-looking villagers from Hosn, beneath the ramparts, line up for a photogenic joust in the courtyard while we lucky guests tackle a mezze of hummus, vine leaves and kibbeh – before a main course of friki (roasted green wheat, chicken and almonds) that leaves us staggering across the cobbles afterwards.

Catering manager Marla is explaining in Arabic and French why she drew the line at serving grilled kebabs as well. "People spilt their blood to defend this place," she says grumpily. "It's just not appropriate to be doing so much cooking here."

Kebabs or no kebabs, the banquet in the castle was one of the high points of this month's Silk Road festival, showcasing Syria as a "bridge between east and west". Latter-day "caravans" – sadly minibuses and coaches rather than the camel trains of yesteryear – criss-crossed the country for a week to take in its sights and a dazzling display of culture, food, music and folklore.

It's an ambitious marketing exercise the government hopes will boost the already rising numbers of foreign visitors to what is still a fairly unusual destination in a volatile and unforgiving region. Tourism is helping bring this country in from the cold.

Krak des Chevaliers is a magnificent example of Syria's many attractions – and of the difficulties of promoting them. Seized from the Arabs in 1099 and expanded by the Crusaders, it is – as the young TE Lawrence (of Arabia) argued before the first world war – the finest specimen of dozens of castles that mark two centuries of European domination of the Holy Land and surrounding area.

Unesco recognises it as a world heritage site. But the signage is poor, there are no audio guides and it is a health and safety nightmare of parapets and stairs without guard rails and toddler-sized holes once used for pouring boiling oil on to attackers. Funding even urgent repairs is a problem, said a worried local engineer scanning the stonework. For all that, to encounter its brooding presence is an unforgettable experience.

Inland, heading east towards Iraq, the beating heart of the Silk Road lies in the amazing desert oasis of Palmyra, where caravans met in ancient times, bringing silk from China and spices from India to Europe. Palmyra looks much as it did when it was "rediscovered" in the 1750s, having been "lost" for centuries, and (maybe) inspired Shelley's Ozymandias ("Look on my works, ye mighty, and despair.")

Head of state ... the image of President Bashar al-Assad is ubiquitous. Photograph: Ian Black Ian Black/Guardian

At the centre of the poet's "colossal wreck" stands the Temple of Bel, with its ramp for driving animals to the sacrificial altar still perfectly intact. Pottering among the ruins under a blazing sun we found American film director Francis Ford Coppola, enchanted by the story of Zenobia, the third century Palmyran queen of legendary beauty, bravery and intelligence.

Coppola was on holiday, he insisted, not scouting for locations. But it would be hard to find a more dramatic setting: Palmyra boasts 30ft Corinthian stone pillars, multi-storey funerary towers, sensational sunrises and Bedouin bumping along on old motorbikes. And, like Krak des Chevaliers, it poses tough questions about balancing authenticity with accessibility, safety and international standards.

Qal'at Fakhreddine, the 17th-century castle overlooking the oasis, offers stunning views, but the day we were visiting it closed – with maddening and uncharacteristic punctuality – at dusk, just as we were clambering up the crumbling ramparts. It was somehow typical of Syria's chaotic hospitality that a few of us were in the end allowed in to watch the fantastic dying of amber and coral light.

The Silk Road festival, launched in 2002, is a very moveable feast – some of its stations are only tenuously linked to the old trade route. This year's "caravans" set out from the Hauran near the Jordanian border, where the jewel is the huge Roman amphitheatre at Bosra, marvellously preserved by being buried under sand for more than 1,000 years.

Syria's cultural and religious diversity and tolerance are being heavily promoted. "Do Americans really know that Syria is the cradle of Christianity?" asked the deputy prime minister Abdullah Dardari. "Do they know they can actually walk on the road to Damascus?" Many Arab Muslims come for the glories of the capital's Umayyad mosque – and some, especially from the Gulf, for baser pleasures. Iranian pilgrims seek out Shia shrines like Sayyida Zeinab. Maaloula, where villagers still speak Aramaic, the language of Christ, and live in houses clinging to a sheer cliffside, is a must. Syria's Jewish community has mostly gone, to Israel or America.

The statistics tell an impressive story: visitor numbers are expected to reach 6m in 2009 and double to 12m by 2014 (though that aspiration begs big questions about capacity). The majority are currently Syrian expats and other Arabs. But the number of European tourists grew by 24% to 270,000 this year. Americans are coming, too, despite trade sanctions: Angelina Jolie and Brad Pitt were here recently – and (like Coppola) had a flattering private meeting with President Bashar al-Assad.

Underpinning the campaign is the wish to create a different image of Syria, not the one encouraged by western governments angered by its support for Hamas in the Palestinian territories, Hizbullah in Lebanon, and its odd-man-out alliance with Iran. The Golan Heights, occupied by Israel since the 1967 Six-Day War, is not on the Silk Road itinerary. But it is not forgotten.

Brand Syria has nothing to say about the country's domestic scene, though the ubiquitous photographs of the president and of his late father, Hafez, tell their own story. Things may be more relaxed these days, but Facebook is banned and a leading human rights activist was arrested the day we headed for Aleppo – although that was not reported in the local media.

Syria today is a safe and peaceful holiday destination. It has not always been. Hama, with its great wooden noria (waterwheels) creaking and groaning as they paddle the Orontes river, is as pretty a place as any. It is also where, in 1982, the government sent in tanks to quell an uprising by the Muslim Brotherhood: rumour has it that the town's best hotel is built on the ruins of the quarter that was bulldozed over the bodies of the thousands who died there. Understandably, it's not something the locals like to discuss with strangers.

Syria's Silk Road is paved with good intentions and goes through many wonderful places. But there's still some way to go before the caravans of today can travel entirely smoothly along it.

• Imaginative Traveller's (08450 778803, imaginative-traveller.com) eight-night Syrian Highlights tour starts at £620pp, including accommodation, transport and the services of tour leader. A local payment of US$200 is payable on arrival. Return flights from Heathrow to Damascus with BMI cost from £324 rtn inc taxes.